System and method for distributed scheduling of transmission resources

ABSTRACT

In accordance with various embodiments, a system and method of distributed transmission resource management in a wireless network is disclosed. The transmission resource allocation is distributed throughout the network to all nodes. In distributed resource management, the resource allocation may be performed by child and/or remote nodes and child and/or remote nodes actively manage transmission resource allocation in the wireless network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to the U.S. provisional patentapplication Ser. No. 62/130,203, filed Mar. 9, 2015, the entirety ofwhich is hereby incorporated herein by reference for all purposes.

TECHNICAL FIELD

This disclosure relates generally to the field of network resourcemanagement and more particularly to timeslot management for datatransmission.

BACKGROUND

The IEEE standard has proposed a Time Slotted Channel Hopping (TSCH)protocol (802.15.4e), which defines a channel hopping medium accesscontrol scheme. FIG. 1 illustrates an exemplary operation 100 ofconventional TSCH protocol. Various nodes in a network are assignedtimeslots within different slot-frames using Absolute Slot Numbers(ASN). Depending on the channel hopping algorithm, each node ‘hops’ to adifferent channel during its allotted timeslot in a given slot-frame totransmit data.

IEEE defined standard for TSCH allows low power devices to support awide range of applications. In TSCH, timeslots synchronization impactspower consumption and preserves power; however, timeslots are assignedby a higher layer of the network. For example, if a network includes acentral node, which is connected to a child node and the child node isconnected to another node—‘grandchild’ node, then timeslot allocationfor the grandchild node will be done by the central node. A centralizedallocation of resource is an easy and less complex solution; however itintroduces high overhead in terms of messaging and energy efficiency.Furthermore, a resource allocation decision made without coordinatingwith routing protocols impacts the efficient functioning of the routingprotocol. For example, a combination of TSCH and Routing Protocol forLow-Power and Lossy Networks (RPL) will cause issues if timeslotallocation is determined by the central node instead of RPL because insuch case, RPL does not get involved in parent selection, which is thecore function of RPL protocol and thus causes conflict. Similarly, acombination of TSCH with other protocols that require activeparticipation of remote nodes in resource management will causeefficiency and at times, functional mismatch of various networkcomponents.

SUMMARY

In accordance with an embodiment a network element is disclosed. Thenetwork element includes a transceiver, and a processor coupled to thetransceiver. The processor is configured to identify at least onetransmission resource for communication in a wireless communicationnetwork, select a parent network node in the wireless communicationnetwork, transmit a request to establish a communication with theselected parent network node using the identified transmission resource,and establish the communication with the parent network node using theidentified transmission resource.

In accordance with another embodiment, a method is disclosed. The methodincludes identifying, by a lower layer network element, at least onetransmission resource for communication in a wireless communicationnetwork, selecting a network node in the wireless communication network,transmitting a request to establish a communication with the selectednetwork node using the identified transmission resource, andestablishing the communication with the network node using theidentified transmission resource.

In accordance with yet another embodiment, an apparatus is disclosed.The apparatus includes a transceiver, and a processor. The processor isconfigured to identify at least one transmission resource forcommunication in a wireless communication network, select a higher layernetwork node in the wireless communication network, transmit a requestto establish a communication with the selected higher layer network nodeusing the identified transmission resource, and establish thecommunication with the higher layer network node using the identifiedtransmission resource, wherein the apparatus is a lower layer networknode in the wireless communication network.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary operation of conventional TSCH protocol.

FIG. 2 illustrates an exemplary wireless network according to anembodiment.

FIG. 3 illustrates an exemplary probability chart of resourceconflict/collision within a 2-hop network using distributed resourcemanagement according to an embodiment.

FIG. 4 illustrates an exemplary flow diagram of a process fordistributed scheduling of transmission resources in a wireless networkaccording to an embodiment.

FIG. 5 illustrates an exemplary structure of network nodes in wirelessnetwork according to an embodiment.

DETAILED DESCRIPTION

The following description provides many different embodiments, orexamples, for implementing different features of the subject matter.These descriptions are merely for illustrative purposes and do not limitthe scope of the invention.

In accordance with various embodiments, a system and method ofdistributed resource management in a network is disclosed. Indistributed resource management, child and/or remote nodes activelyparticipate in allocation and management of transmission resources.

Referring to FIG. 2, an exemplary wireless network 200 is illustratedaccording to an embodiment. Network 200 can be any form of network suchas hierarchical network, mesh network, or the like. Network 200 includesa Central node 220. The Central node 220 can be any wirelesscommunication network element for example, an access point, a networkrelay, a network extender, a wireless router, or any other devicecapable of connecting to a network and provide and manage wirelesscommunication connections to various devices. The central node 220 canalso be referred to the root node for the network 200. The network 200further includes Child nodes 230(1)-(N), Grandchild nodes GC 240(1)-(N),and Greatgrandchild nodes GGC 250(1)-(n). While for explanationpurposes, only one greatgrandchild node GGC 250(N) is shown, the networkcan include many other greatgrandchild nodes 250(1)-(N). Further, thenetwork layers are not limited to the ones illustrated. The network 200can include many other layers with respect to the Central node 220 andeach child node can have multilayer networks below its own layer forexample, as illustrated the child node 230(3) has multiple GC nodesGC240(3 a)-(3 n). Similarly, depending on the network layout, morecomplex network structures can be created to implement embodimentsdescribed herein. Child nodes, GC nodes, and GCC nodes can also bereferred to a lower layer network nodes in the network where the centralnode controls all transmission resources. While for exemplary andsimplification purposes only one greatgrandchild node GGC 250(N) and fewof the other nodes are shown; however, network 200 can include manyChild, GC, and GGC nodes and further there can be many more network nodelayers beyond GGC nodes also.

The network layer relations among various nodes can be identified basedon the connection distance from the central node 220. For example, thecentral node 220 can be considered as the root node or the first layernode. Child nodes 230 can be identified as the second network layernodes and the center node 220 can be the parent node for child nodes230. Similarly, GC nodes can be identified as the third network layernodes and GGC nodes 250 can be identified as the fourth network layernodes and the like. Each parent node can be identified as the highernetwork layer node for the child or grandchild node for example, GCnodes 240 can be parent nodes for GGC nodes 250, Child nodes 230 can beparent nodes for GC nodes 240, Center node 220 can be parent node forchild nodes 230 and the like. Each parent node can be considered as thehigher network layer node for a child or grandchild node and the like.

Conventionally, when a new node enters a network, then the node requestsa handshaking to the central node 220 to establish communication eitherdirectly or through intermediate nodes such as for example, Child nodes230, GC nodes 240, GGC nodes 250, or the like, depending on at thenetwork layer the new node is entering the network 200. As statedherein, conventionally the central node controls and allocatestransmission resources in the network and all other networknodes/elements that are lower layer nodes/elements, depend on thecentral node for resource allocation. Transmission resources inconventional network are assigned by the central or root nodes and childnode or lower layer nodes do not have control over transmission resourceallocations.

According to an embodiment, when a new network node wants to join thenetwork 200, then the new node ‘listens’ to transmission resources forexample transmission channels and network traffic before transmittingany higher level messages to the higher network layers for a parent nodeselection negotiation. Once the new node obtains channel information;i.e., channel busy or not busy, noise, and other channel conditions,etc. then the new node selects a suitable parent node for communicationand then selects available transmission resources such as time slots,channel offsets, and other related parameters if needed, for theselected parent node randomly from an available set of parameters. Afterselecting the parameters, the new node sends an association requestindicating the timeslot/channel offset pair and other parameters ifneeded, to be used for communication with the parent node. If the parentnode has no channel conflict, it sends a positive response to the newnode and both nodes start using the negotiated resources. According toan embodiment, a child node or lower network layer node can identify atransmission resource for communication and the transmission resourceallocation is distributed to lower network layer nodes. Thus, the childnode or lower network layer node does not have to depend on the centralnode for transmission resource allocation.

According to another embodiment, during the communication operation, ifthe Received Signal Strength Indicator (RSSI) or the retransmissions ofpackets increases within selected transmission resources (e.g.,timeslot, channel, or the like), then a node in the network 200 canenter into a probing state for a predetermined or random amount of timeto determine whether the condition of selected transmission resourcesimproves. If the condition of selected transmission resources improvewithin the predetermined of random time period, then the node revertsback to normal operation. If transmission resource conditions do notimprove within the predetermined or random time period, then the nodeleaves the conflicting transmission resources and restarts the randomtransmission resource selection and assignment process. If a noderequires more transmission resources during the operation, then the nodecan randomly select more available transmission resources and startusing them as described herein. This allows for the node to accommodateits resources based on its traffic needs; thus, resulting in betterperformance for the network. On the other hand, the node can decreasethe number of transmission resources if the traffic requirement getslower, thus saving energy instead of performance. In this resourcemanagement operation, the central node does not get involved unless anode is communicating with the central node directly. All resourceselections and decisions are made at the lower network level between twonodes.

Referring to FIG. 3, an exemplary probability of resourceconflict/collision within a 2-hop network using distributed resourcemanagement is illustrates according to an embodiment. The collisionprobability is illustrated vs. a number of contending nodes for 340Resources. The exemplary conflict probability is based on a networkwhere 10 consecutive nodes contend for a random resource out of theavailable 340 resources. As illustrated, at first instance, a conflictresults for only 10%-15% of the time. After running into a resourceconflict, when nodes back-off and retry contending for resources, thenthe retrials conflict probability gets even further low. Every retryresults in much lower probability of resource conflict. The selection ofresources can be done using any stochastic process such as for example,Transient Markov Chain, or the like, which can guarantee to converge toa solution for random selection of resources. This approach resolvesscheduling problem in a dynamic and distributed way and in the end, aresource setup converges.

The conflict free deterministic solutions also need to resolve hiddennodes problem in a network. Hidden nodes in a wireless network are nodesthat a given node cannot ‘see’ means those nodes are out of range ofother nodes. The problem with hidden nodes is that when hidden nodesstart to send packets simultaneously to a receiving node. Because thesenodes are ‘hidden’ from each other or they are out of range from eachother, they cannot detect a collision while transmitting packets.According to another embodiment, for a conflict free deterministicscheduling, beacon payload may be used to communicate resourceavailability. A node may use beacon payload to broadcast/communicate aperiodic message in the network that may include timeslots and channeloffset that are used by the node. The beacon message can indicatetransmission resources of the node with the following exemplary options:

TX: Available for Transmission RX: Available for Reception

No-TX: Not available for TransmissionNo-RX: Not available for ReceptionShared: Multiple nodes will be sharing the transmission resource

While exemplary resource indication are illustrated; however, anyindication can be used to communicate the status of resource usage of anode to avoid conflict with other nodes in the network. For example,lower layer nodes can communicate directly with each other without theintervention of a central node to negotiate available resources andwithout advertising or broadcasting their status. Further, each resourcecan have certain expiration time for transmission resources for example,if a node broadcasts that it will be using a resource ‘A’, then if thenode does not use the resource ‘A’ or keeps using resource ‘A’, thenthere can be a possibility that the node may block resource ‘A’ for longperiod of time. To avoid such conflict, according to an embodiment, eachresource can have an associated ‘life time’ timer. For example, aftercapturing resource ‘A’, a node can use resource ‘A’ for a predeterminedperiod of time and at the expiration of ‘life time’ timer, resource ‘A’usage for the node may expire and resource ‘A’ will be available forother nodes to contend for.

According to an embodiment, each node in the network may ‘listen’ to itsneighbor's beacons to get information on its neighborhood resourceusage. The resource usage information can be communicated in variousforms such as for example, a resource table with related information maybe included in the beacon or the like. When a node receives the resourceusage information from its neighbor node's beacon, then the node canconstruct its own resource usage information data such as for example,it can create its own resource usage table to keep track neighborhoodresource usage. Any node that desires to allocate a resource towardsanother node can select an available resource, for example, resource‘X’, from the resource usage table and send a request to use resource‘X’. If the intended receiver node of the resource request detects noconflict in allocating resource ‘X’, then it can respond with a positiveresponse. After a ‘handshaking’ between two nodes, both nodes can updatetheir resource usage table to indicate the usage allocation of resource‘X’.

Initially, the resource usage broadcast and neighbor resource usagetable processing may increase the number of beacons a node may receiveand process; however, the beacon broadcasting may be suppressedgradually in time when the resource usage tables stabilize and are notupdated frequently to conserve energy without losing synchronizationwith the network. If a conflict is detected in resource utilization,then as explained herein, the conflicted resource can be released withina predetermined timeout period if the conflict conditions do notimprove. The distributed resource usage communication and allocationprovides a dynamic and deterministic solution for resource scheduling.The resource allocation can be done using the frequency, time, and spacediversity to its full extent. The resources can be dynamically droppedor allocated according to the changing needs of network nodes to improvethe performance of energy consumption.

According to yet another embodiment, a lower layer node can broadcast a‘page’ of resource information. A page can be a collection of resourcesthat a node may desire to use or is using. The ‘page’ can also be acollection/group of resources, grouped during initialconfiguration/setup of the network. Each node in the network canbroadcast its ‘page’ usage periodically within their beacon payload. Apage usage can be marked with the following exemplary indications:

Uplink Page: The page is owned by the parent node and a resource hasbeen assigned for this node's transmission to its parent.Downlink Page: The page is owned by the node itself and all resourceswithin the page are reserved for the node's usage towards itschild/grandchild etc. nodes.Heard Page: Indicates that another node within the 1-hop neighborhood isusing this page, making it impossible for this node to use the samepage.Every node can listen to its neighbor's beacons to get its neighborhoodusage ‘page’ and use the received information to construct its ownresource information table.

According to an exemplary embodiment, two types of allocation can bemade for each page: 1) Uplink and 2) Downlink. The uplink is typicallyassigned by a parent node during association and the uplink page ismatched with the Downlink page of the selected parent node. The parentnode may assign a resource from the Downlink page of its own resourcepage as an uplink resource to a newly joined node. The resourceallocation includes at least a transmission and a reception resource fortwo-way communication.

The downlink page can be taken by a node by itself. If any conflict isdetected in using the uplink and downlink resources then a ‘life timer’can be assigned to each resource as explained herein and if theconditions do not improve, then conflicted resources can be releasedwithin a predetermined or random timeout interval. According to anotherembodiment, a full dynamic and deterministic solution can be provided toresource scheduling problem. The overhead of resource negotiation can bereduced as a page allocation can reserve multiple resources for a node.When a resource page is underutilized, then the resources can be releaseafter certain idle time for example, if a node reserves a page ofresources and if resources are not used for certain predetermined orrandom time period, then the node may be required to release resourcesand update its beacon broadcast. The resources can be increased ordecreased within a page as these resources are already reserved andowned by a node. When a page includes both types of resources:transmission and reception, then the page cannot be identified as singletransmission or reception resource.

Referring to FIG. 4, an exemplary flow diagram 400 of a process fordistributed scheduling of transmission resources in a wireless networkis illustrated according to an embodiment. A node that desires to join anetwork can initially listen to network at 410 to identify atransmission resource for communication. If the node cannot locateresources at 415, then the node continues to monitor network resourcesat 410. If the node identifies available transmission resources, then at420, the node selects a suitable parent node to associate with. At 425,the node selects transmission parameters such as time slots, channeloffsets, and the like for communication with the selected parent nodeand at 430, the node transmits an association request to the selectedparent node. At 432, the node determines if it received any responsefrom the parent node. If the node does not receive any response, thenthis may indicate that there may be interference in the transmissionmedium. In that case, the node may try to connect to the same parent fora predetermined number of times or a predetermined period of time. At434, the node determines if either the predetermined number of retiresor the predetermined amount of time period has expired. If the number ofretires or time period has not expired, then the node continues to tryto establish the communication with the selected parent node at 430. Ifat 434 the node determines that the predetermined number of retires orthe time period has expired and the node is unable to establish acommunication link with the selected parent, then the node may proceedto select a different parent at 420.

If the node receives a response form the selected parent node then at435, the node determines whether it received a positive response for theselected parent node. The node may find certain transmission resourcesas available for communication with the parent node; however, theselected parent node may have already allocated those resources to someother nodes. Based on the resource availability, the parent node maysend a positive or a negative response to the node. If the selectedparent node does not have any channel conflict for the selectedtransmission resources, then the parent node may send a positiveresponse to the node. If the node does not receive a positive responseand the replay is negative (e.g., no links available for communication),then the node restarts the process for selecting a suitable parent nodeto communicate with at 420. If the node receives a positive responsefrom the selected node, then the node establishes a connection andassociation with the selected parent node at 440 and at 445 broadcastsits resource usage to other nodes in the network. As explained, the nodecan periodically broadcast a table or page of resources in its beaconsbased on a given implementation of the network protocol.

The node can continue to monitor the condition of transmissionresources. At 450, the node determines whether the transmission resourcecondition (e.g., channel condition) has been deteriorated. The resourceconditions can be determined based on the number of retransmission inthe transmission resource, error rate, RSSI, and various other channelcondition parameters. The node may determine whether resource conditionsare within certain predetermined range and if resource conditions arenot within predetermined range, then the resource can be identified asdeteriorated. For example, if the measured RSSI on the resource is morethan a predetermined range considered to be good for transmission, thenthe node can determine that the resource condition has deteriorated. Ifthe transmission resource has not deteriorated, then the node continuesto use the resources and broadcasts them in its beacons. If thecondition of transmission resources has deteriorated, then the nodeenters into a probing state at 455 for a predetermined period of time.If after the predetermined period, at 460 if it is determines that thetransmission resource conditions have improved, then the node resumesnormal operation at 465 by using the resources for transmission. If thetransmission resource conditions do not improve after the predeterminedperiod of time, then the node releases the conflicting/deterioratedresources at 470 and restarts random resource selection and assignmentat 410.

Referring to FIG. 5, an exemplary structure of network nodes(child/grandchild, intermediate, central, etc.) in wireless network 500is illustrated according to an embodiment. Network 500 includes anexemplary network node 510. The network node 510 can be any wirelesscommunication network node for example, an industrial control system, awireless communication device, a smart phone, or any other communicationdevice capable of wireless communication. The network node 510 includesa transceiver 512, a processor 514, a storage device 516, and an antenna518 among various other system components. Although for explanation,simple elements are shown; however, the network node 510 can includevarious others system components and multiple elements for example, thenetwork node 510 can have multiple processors, antennas, storagedevices, transceivers, displays, user interface, and the like.

The network 500 also includes various other wireless communicationdevices such as for example, nodes 540 and 550. While for exemplarypurposes only illustrated nodes are described; however, network 500 canhave multiple nodes such as for example as illustrated in FIG. 2. Thenetwork 500 can also include many other devices capable of wirelesslycommunicating with the network node 510 such as control systems,printers, consumer electronic devices, smart phones, and various otherdevices and systems capable of wireless communication. Further, thenetwork node 510 can also be communicatively coupled to other networknodes in a mesh or other types of network schemes. Each of the networknodes 540 and 550 may also include various other system components suchas transceivers 542 and 552, processors 544 and 554, storage devices 546and 556, and other components like displays, keyboards, antennas, otheruser interface, and the like (not shown). These nodes may communicatewith each other in the network 500 using embodiments described hereinfor distributed selection of transmission resources for improvedresource utilization and power efficiency.

The foregoing outlines features of several embodiments so that those ofordinary skill in the art may better understand various aspects of thepresent disclosure. Those of ordinary skill in the art should appreciatethat they may readily use the present disclosure as a basis fordesigning or modifying other processes and structures for carrying outthe same purposes and/or achieving the same advantages of variousembodiments introduced herein. Those of ordinary skill in the art shouldalso realize that such equivalent constructions do not depart from thespirit and scope of the present disclosure, and that they may makevarious changes, substitutions, and alterations herein without departingfrom the spirit and scope of the present disclosure.

Although the subject matter has been described in language specific tostructural features or methodological acts, it is to be understood thatthe subject matter of the appended claims is not necessarily limited tothe specific features or acts described above. Rather, the specificfeatures and acts described above are disclosed as example forms ofimplementing at least some of the claims. Various operations ofembodiments are provided herein. The order in which some or all of theoperations are described should not be construed to imply that theseoperations are necessarily order dependent. Alternative ordering will beappreciated having the benefit of this description. Further, it will beunderstood that not all operations are necessarily present in eachembodiment provided herein. Also, it will be understood that not alloperations are necessary in some embodiments.

Moreover, “exemplary” is used herein to mean serving as an example,instance, illustration, etc., and not necessarily as advantageous. Also,although the disclosure has been shown and described with respect to oneor more implementations, equivalent alterations and modifications willoccur to others of ordinary skill in the art based upon a reading andunderstanding of this specification and the annexed drawings. Thedisclosure comprises all such modifications and alterations and islimited only by the scope of the following claims. In particular regardto the various functions performed by the above described components(e.g., elements, resources, etc.), the terms used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure. In addition, while aparticular feature of the disclosure may have been disclosed withrespect to only one of several implementations, such feature may becombined with one or more other features of the other implementations asmay be desired and advantageous for any given or particular application.

What is claimed is:
 1. A network element comprising: a transceiver; anda processor coupled to the transceiver, the processor is configured toidentify at least one transmission resource for communication in awireless communication network, select a parent network node in thewireless communication network, transmit a request to establish acommunication with the selected parent network node using the identifiedtransmission resource, and establish the communication with the parentnetwork node using the identified transmission resource.
 2. The networkelement of claim 1, wherein the network element is a lower layer networknode in the wireless communication network, and the parent network nodeis a higher layer network node in the wireless communication network. 3.The network element of claim 1, wherein the processor is furtherconfigured to: broadcast transmission resource usage in the wirelessnetwork, wherein the broadcast indicates the at least one transmissionresource as resource allocated to the network element for communicationin the wireless communication network.
 4. The network element of claim3, wherein the processor is configured to broadcast the transmissionresource usage in a beacon transmission.
 5. The network element of claim3, wherein the broadcast identifies a plurality of transmissionresources allocated to the network element for communication in thewireless communication network.
 6. The network element of claim 1,wherein the transmission resource includes one or more of acommunication timeslot and a channel offset.
 7. The network element ofclaim 1, wherein the processor is further configured to: determinewhether one or more of a Received Signal Strength Indicator (RSSI) or anumber of retransmissions on the identified transmission resource iswithin a predetermined range, and release the transmission resource, ifthe RSSI or the number of retransmissions on the identified transmissionresource is not within the predetermined range for a predeterminedperiod of time.
 8. The network element of claim 1, wherein the parentnode is a central node in the wireless communication network.
 9. Amethod comprising: identifying, by a lower layer network element, atleast one transmission resource for communication in a wirelesscommunication network; selecting a network node in the wirelesscommunication network; transmitting a request to establish acommunication with the selected network node using the identifiedtransmission resource; and establishing the communication with thenetwork node using the identified transmission resource.
 10. The methodof claim 9, wherein network wherein the network node is a higher layernetwork node in the wireless communication network.
 11. The method ofclaim 10, further comprising: broadcasting transmission resource usagein the wireless communication network, wherein the broadcastingindicates the at least one transmission resource as resource allocatedto the lower layer network element for communication in the wirelesscommunication network.
 12. The method of claim 11, wherein thetransmission resource usage is broadcasted in a beacon transmission. 13.The method of claim 11, wherein the broadcast identifies a plurality oftransmission resources allocated to the lower layer network element forcommunication in the wireless communication network.
 14. The method ofclaim 9, wherein the transmission resource includes one or more of acommunication timeslot and a channel offset.
 15. The method of claim 9,further comprising: determining whether one or more of a Received SignalStrength Indicator (RSSI) or a number of retransmissions on theidentified transmission resource is within a predetermined range, andreleasing the transmission resource, if the RSSI or the number ofretransmissions on the identified transmission resource is not withinthe predetermined range for a predetermined period of time.
 16. Anapparatus comprising: a transceiver, and a processor coupled to thetransceiver, the processor is configured to identify at least onetransmission resource for communication in a wireless communicationnetwork; select a higher layer network node in the wirelesscommunication network; transmit a request to establish a communicationwith the selected higher layer network node using the identifiedtransmission resource; and establish the communication with the higherlayer network node using the identified transmission resource, whereinthe apparatus is a lower layer network node in the wirelesscommunication network.
 17. The apparatus of claim 16, wherein theprocessor is further configured to determine at least one transmissioncondition of the at least one transmission resource; enter into aprobing state for a predetermined period of time, if the transmissioncondition of the at least one transmission resource not within apredetermined range; and releasing the transmission resource, if thetransmission condition of the at least one transmission resource is notwithin the predetermined range for a predetermined period of time. 18.The apparatus of claim 17, wherein the transmission condition includesone or more of a Received Signal Strength Indicator (RSSI), and a numberof retransmissions on the at least one transmission resource.
 19. Theapparatus of claim 16, wherein the processor is further configured tobroadcast a beacon in the wireless communication network, wherein thebeacon identifies the at least one transmission resource as resourceallocated to the apparatus for communication in the wirelesscommunication network.
 20. The apparatus of claim 16, wherein thetransmission resource includes one or more of a communication timeslotand a channel offset.